- Title
- Effect of climate change on groundwater at potentially contaminated sites
- Creator
- Mohammed, Adnan
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2022
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Scientists and policymakers have studied the climatic and anthropogenic factors that influence groundwater resources; this research further considered these impacts on contaminated aquifer remediation and management strategies. The change in groundwater hydraulics (i.e., quantity) at contaminated sites will directly affect hydrogeochemical properties, consequently selecting the best groundwater remediation options. As well, choosing desired remediation technologies is influenced by groundwater level (GWL)fluctuation, which may reduce the efficiency and effectiveness of such strategies. Previous studies revealed that the risks posed by climate change and extended drought and floods are likely to have unprecedented consequences for groundwater contamination management. Not many studies have investigated the impact of climate change on fluctuations in groundwater table fluctuations or the subsequent implications for contaminated land management/remediation techniques. This study utilised a rare set of long-term concurrent monitoring data for groundwater hydraulics and meteorological data obtained from government agencies. The research presented a correlation and pattern between the changes in climate as evidenced by rainfall patterns and fluctuations in the groundwater table. The research investigated case study sites to establish the hypothesis are Wee Waa and Condobolin, both in New South Wales (NSW), and a contaminated site at Edinburgh RAAF base in South Australia (SA). The research is based on the hypothesis that climatic factors such as rainfall, temperature, and evapotranspiration will impact contaminated aquifer management strategies and the effectiveness of remediation processes and the fluctuations occurring in groundwater hydraulics conditions. A detailed statistical analysis was applied to an extensive data set from long-term hydrogeological and meteorological datasets from 1969 to 2012. The study categorises the zoning for two types of land activities in the study areas. Twenty monitoring stations were selected. Statistical analysis was conducted using sets of monitoring locations based on land-use and non-land use areas. The time-series statistical analysis methodology (1993-2014) served to analyse the regression between GWL and climatic factors at the contaminated site in SA. All the study sites are carefully selected to minimise the anthropogenic effect on GWL, such as irrigation and nearby abstraction wells, and the research presents the effects of climatic change. Detailed evaluation of the data using time series and multiple regression analyses reveals a strong correlation between climatic factors and drawdown in GWL (p < 0.05) in both study areas in NSW (Wee Waa and Condobolin) whether with or without land-use activities. This drawdown in groundwater level is attributed mainly to climatic factors and less to anthropogenic and land use activities. Rainfall has exhibited a significant positive correlation (confidence level 95%) with GWL and a negative correlation with temperature. The unsaturated sub surface’s geology and/or soil properties considerably influence groundwater recharge and have not been considered here. Unlike the Wee Waa and Condobolin study, the Edinburgh site study was much more detailed in that as well as investigating the effect of rainfall pattern on fluctuations in the groundwater table, changes in the concentration of contaminant (i.e., trichloroethylene (TCE)) and other geochemical properties were evident. The aquifer's geochemical parameters (pH, electrical conductivity (EC) and dissolved oxygen (DO)) and GWL fluctuation at the Edinburgh site demonstrated no significant correlations p > 0.05, except in one monitoring station GW123. Temperature and evapotranspiration positively correlate with GWL, very different to what has been published in the literature except for one monitoring station. The literature generally agrees that there is a negative correlation between temperature and evapotranspiration with GWL, yet our analysis exhibits a positive one. The possible reason for that difference is further factors such as aquifer geological formation and other natural factors posing additional impacts that were not previously considered. While there was no significant correlation between (TCE) concentration and GWL there was a positive correlation with temperature and evapotranspiration in half of the monitoring stations (Spearman correlation r < 0.50, p > 0.05). This research demonstrated that increasing TCE concentrations of groundwater drawdowns was due to climatic factors. Finally, climatic factors significantly impact on GWL fluctuation but a significant correlation between these factors themselves might further affect the GWL. Limitations that affect the research, such as soil type, aquifer geological layer configuration, crop water consumption, vegetation cover, human activities, etc., may need to be taken into account to obtain further accurate results for statistical analysis. Recommendations such as simulation modelling (MODFLOW) and employing a fate and transport model for contaminants’ concentration behaviour must be conducted. An extreme event like a natural disaster such as drought and flooding need to be analysed as well.
- Subject
- climate change; remediation; contaminated land; groundwater; recharge
- Identifier
- http://hdl.handle.net/1959.13/1500107
- Identifier
- uon:54848
- Rights
- Copyright 2022 Adnan Mohammed
- Language
- eng
- Full Text
- Hits: 367
- Visitors: 439
- Downloads: 120
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 3 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 310 KB | Adobe Acrobat PDF | View Details Download |